The Velocity Dependence of Dynamic Capillary Pressure During Imbibition Displacement in Microscale Quartz Capillaries

摘要

Studies have been done to elucidate the velocity dependence of dynamic capillary pressure in the process of water displacing oil under constant pressure drops in hydrophilic capillaries with 0.92 μm in radius. Experimental results show that this dependence is closely correlated with the relative viscosities of the liquids involved. When the liquids are equal in viscosity, the displacement proceeds with constant rate and the dynamic capillary pressure stays almost unchanged, while it increases gradually with a increase in velocity in the case of water displacing more viscous oil, in contrast, it decreases gradually with a reduction in velocity when water displaces less viscous oil.